What is a Hand Hammered Bell?

Posted by Getzen on March 10th, 2009

There’s a lot of confusion about what a hand hammered, one piece bell really is. Not to mention the confusion about what makes them so special. Well, maybe not confusion so much as misinformation. The market is flooded with professional trumpets that have, so called, hand hammered, one piece bells. Thus creating images of craftsmen of old using nothing more than strength, determination, and skill to turn a flat piece of brass into an expertly crafted bell. In today’s industry, that couldn’t be further from reality.

In many cases, the way trumpet bells were crafted years ago has been left by the wayside. The overall specs and dimensions may be unchanged, but the manufacturing processes are light years apart. Do you think there were hydraulic presses slamming brass into bell forms at the turn of the century? What about computer controlled spinning lathes forcing a bell blank tight to a mandrel? While technology has made many aspects of manufacturing better, some advances have actually tainted the finished product. How many times have you heard someone say his or her 50 year old trumpet plays so much better than a new one? Why do you think that is? The brand names may be the same, but, as the saying goes, they just don’t build them like they used to.

What makes a true hand hammered, one piece bell? What’s the right way to craft one? I’m glad you asked. As I see it, there are several questions that must be answered. What’s the bell made from? How’s the pattern made? How’s the seam formed/brazed? How’s the bell formed? How’s the bell spun? The answers to these questions are what separate the “wanna be” bells from the real deal.

What’s the bell made from?

The Right Way: First and foremost, a true hand hammered, one piece bell starts out as a roll of plain old sheet brass. Sure there are different alloys and thicknesses, but the common thread is that they all start as nothing more than a simple sheet.

The Wrong Way: There are some out there that confuse seamless bells with true one piece bells. Seamless bells are formed from either a single piece of tubing or by electroplating a thick layer of metal onto a bell mandrel. Both of these methods have their advantages. We use seamless tube bells for our student line of trumpets and cornets. They’re inexpensive and durable while providing easy tonal production. However, these bells offer little in the way of projection or character. Electroplated bells allow us, and others, to produce copper bells at an affordable price. Despite the positives, these too are a long way from hand hammered, one piece bells in terms of performance.

Brass Rolls

How is the pattern made?

The Right Way: Simply put, the pattern is made by cutting the brass sheet to shape … ideally by hand. That is, someone lays a template over the brass, scribes an outline, and uses shears to cut along that line. No stamping, no laser cutting, no computer controlled cutting tools at all. In fact, if we got rid of our electric shears and went back to manual tin snips, cutting a bell pattern would look just like it did before the Great War.

Bell Patterns

The Wrong Way: Keep reading. This and the next two “Right Ways” are covered by just one “Wrong Way” used by some of our biggest competitors.

How is the seam formed/brazed?

The Right Way: After the pattern is cut, it’s placed in a hand press. Here the flat pattern is bent in bringing the two outside edges together. Basically, this press is nothing more than a table with a slot down the middle. The pattern is laid on this table with the slot running from tail to flare. A lever is pulled and the craftsman’s strength is used to push a piece of steel through the slot taking the brass along with it. This folds the brass pattern in half. Then a hand tool is used to cut tiny notches at set intervals along the length of the pattern. The notches work to lock the sides together and form a perfect seam. This seam is then hammered, by hand, tightly together. From here, it’s on to the torch room where the seam is brazed, again by hand, using a special brazing paste and torch. It’s a hot, noisy job, but one that requires the human touch to be done just right. After being brazed, the pattern begins to look like a trumpet bell for the first time. It may be a burned trumpet bell that was just run over by a steamroller, but a trumpet bell nonetheless.

Bell Seam Hammering

How is the blank formed?

The Right Way: This is where things get interesting and a hand hammered bell gets its name. It’s at this point the hammers come out. The burned, flattened bell pattern is taken into the aptly named Hammer Room. Here, the craftsmen involved start by “opening up” the pattern. In a nutshell they slide the pattern over a vertical, steel bell mandrel and repeatedly force it down onto the steel. Think of it as if they were trying to throw the bell straight down over and over again. The action forces the tight pattern to open up, meeting the mandrel’s taper. They’re beginning to open the throat of the bell, but we’re still a long way from finished.

Once the throat is opened, it’s hammer time. The pattern is again placed on a steel bell mandrel only this time it’s horizontal. Large wooden and/or rawhide mallets are used to, let’s just say, caress the brass to shape. Every inch of the bell’s surface from tail to flare rim are hit again and again as the bell is formed. The blows rain down like a one sided prizefight until the shape is just right.

This step is the key to what makes a hand hammered bell so special. Keep in mind that throughout this hammering the brass is work hardened. The brass must be re-softened via torch annealing to continue. It’s this hammering, hardening, softening, hammering, hardening, softening, etc… that gives the bell its truly unique tonal characteristics. Some think it’s the lateral seam that’s the key to a hand hammered, one piece bell’s superiority over two piece designs. The theory is that a two piece bell’s radial seam blocks resonance traveling through the bell while the lateral seam does not. While the seam plays a part to the bell’s overall performance, it’s just a small part of the whole. If the key was the seam, a seamless bell should be the best of the bunch because there is no hindrance at all. No, the real magic comes from the extremely complex and time intensive tempering of the brass. The kind of tempering you can only achieve with strong arms, a hammer, and a torch.

Bell Hammering

The Wrong Way: As I mentioned before, this “Wrong Way” is the competitions’ answer to the three previous “Right Ways” we practice when crafting a true hand hammered bell.

Like us, many of the competition start with a simple piece of brass sheet. However, the similarities end there. Rather than cutting the bell pattern and forming it into a blank with little more than the skilled hands of a craftsman, the majority of work is done by machine.

The brass sheet is fed into a hydraulic forming press. Here, the sheet is sandwiched between a mold and a hydraulic bladder. The bladder is inflated and, under thousands of pounds of brute force, the brass is forced to the mold. This exposes the brass sheet to an extremely high amount of pressure and stress. Due to its lack of touch and feel, the machine only knows one thing, go from flat to formed. After this forming, the excess material of the sheet is cut away and you’re left with what looks like a bulbous, overly inflated trumpet bell split down the middle.

To form the bell’s seam the blank is put into another hydraulic press and bent to bring the two sides together. Again, no feel, no touch, just unbent and bent. Once the seam is brazed, the blank is already recognizable as a trumpet bell. It’s now that the hand hammering is done. However, since the bulk of the forming was done in the hydraulic press before a hammer was ever swung, it takes very little time and very few blows to achieve the desired shape. Less hand hammering means things move along much faster. It also means there is much less annealing needed. Think back, remember when I said the real key to a hand hammered, one piece bell was the hammering and annealing? All of that great tempering of the brass is sacrificed here for speed. Sadly, in the world of manufacturing faster equals cheaper and, in some minds, that means better. Now I guess you could argue that some hammering is better than none and you’d be right. Although, that’s like saying $5 is better than none, but wouldn’t you rather have $500?

Annealed Bells

How is the bell spun?

The Right Way: When it leaves the hammer room, a hand hammered, one piece bell looks more like a brass funnel than a trumpet bell. It takes a pretty good imagination to see the shape of things to come. The journey of turning this rough looking funnel into a full fledged trumpet bell comes with it’s first round of spinning.

Rather than being spun on a mandrel, like every other bell, it’s slid inside a special cup and hand spun to form a rough bell flare. This inside out spinning is used because of the rough shape of the funnel. This is the only way to ease it into a traditional bell shape. Trying to go from funnel right to a finished bell would expose the brass to damaging stress and metal fatigue. After this first spinning, the bell is pretty ugly, but it’s starting to shape up.

After one last pass through the annealing room, the hand hammered, one piece bell follows the path taken by every other bell we make. It’s hand spun on a steel mandrel mounted to a special lathe. Hand spinning is a key aspect of bell making. It’s all about the feel of the brass, the resistance of the tool, and the smoothness of the surface. Things much too complex for an automated system to monitor and react to efficiently. Yet again, the key to quality lies in the skilled hands of a trained craftsman.

The Wrong Way: Once again, superior craftsmanship is sacrificed for speed. Robo-spinners go from start to finish in one mighty pass. As before, there’s no feel and no touch, just unspun and spun. Their job is to smash the brass into place rather than smoothly easing it down to size. Think of it in carpentry terms. Say you’re building a table and need to cut a board to length. You can do it with either an axe or a circular saw. The end result might be the same, two pieces of wood, but the quality of the two pieces couldn’t be farther apart. What’s the old saying? There’s the fast way and then there’s the right way.

The real kicker in this whole thing comes when you realize that the “Wrong Ways” mentioned in this article are actually the best of the bunch. Some manufacturers completely skip the hammering process and rely solely on hydro-forming to go from brass sheet to the spinning lathe. Almost every benefit of a true one piece bell is lost. The worst offenders are those that hammer their bells for nothing more than show. Just so they can market them as hand hammered. I once saw an ad for a trumpet hailing its hand hammered bell. The ad featured a photograph of a finished bell on a mandrel being tapped with a ball peen hammer. Sure there’s a hand, a hammer, and a bell, but that’s not exactly the right idea guys.

Keep all of this in mind the next time you hear or read the term “hand hammered, one piece bell”. While the description might be technically accurate, there’s a lot more to it than mere technicalities. When a salesman tells you how great a trumpet is because of its bell, ask him some of the above questions. He might not know the answers, but if he answers them all with the “Right Ways” mentioned here chances are he’s trying to sell you a Getzen.

5 Responses to “What is a Hand Hammered Bell?”

  1. Melvin Farris Says:

    Very interesting article about the hand hammered bell. Although I do not own a Getzen trumpet (I am an adult amateur who plays a lot, in jazz, concert band and symphony orchestras) I recently had an opportunity to try a Getzen Custom trumpet. I was very impressed by the clear sound, easy response and sonic quality from low pedal tones to very high g”’. I was highly impressed by this instrument.

  2. tom flynn Says:

    thank you for the wonderful article on “hand hammered bell” production. I own 2 Severinsen Eterna trumpets, vintage 1968. One is a large bore and the other a ML bore. The large bore horn is noticeably lighter than the ML. Were these bells made differently than Bach or Schilke and if so, how… to the best of your knowledge? Thank you for your continued source of information.

    Tom Flynn
    Auburn, Maine

  3. Kirk Berry Says:

    Looking for a large bore silver b flat trumpet.
    Live in Germantown Maryland.

    Where can I go?

    Regards,

    Kirk Berry

  4. josh Says:

    Hi Kirk,

    Try using our dealer locator (http://getzen.com/dealer/) to find a music shop close to you. Call ahead to see if they have any horns in stock.

    Take care,

    Josh

  5. John Says:

    Is their any way you could clue people in as to which companies truly make real hand hammered bells and which ones are just playing a name game? I only ask because for the most part much of the instrument sales market is about half truths, lies, mis-informations, secrets and marketing mumbo-jumbo! It is easier to get the truth out of a trial lawyer then it is to get the truth out of musical instrument companies! Often one get’s caned responces that tell one a lot of nothing with more words used then shouldhave been!

    Thanks for the Gazette it is full of good information! As a person that hates Monel valves it is nice to see some truthful researcha nd findings put out! I only wish more people where reached by your publication!

    Sincerely,

    John

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